Comments by "Lepi Doptera" (@lepidoptera9337) on "Lecture 1: Classical Field Theories and Principle of Locality" video.

  1. Some professors were teaching with overhead projectors even 50 years ago. It didn't make the lectures any better. What is important is what you teach, not how.
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  2. He is pointing out that the problem occurred in classical physics and it has nothing to do with quantum field theory. In classical physics we can make repetitive measurements on the same classical body at spacetime points (t0, x0), (t1, x1) etc.. The theory then translates that into a dynamical path variable x(t), even though that is NOT what we are actually observing. In modern physics we have to let go of the x(t) path completely. It simply doesn't exist.
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